A riser is a pipe extending between a subsea installation and a floating installation for transferring fluids and or signals between equipment at the two installations. There may be produced hydrocarbons, drilling fluids, injection fluids, etc. transferred by the riser. The floating installation which will move due to changing weather conditions, wind waves, currents, etc. is normally given a safe operation window. Such a safe operation window may for instance define an area wherein the installation may move without danger of damaging the equipment, wind conditions where the installation can be kept within this area, etc. However, there are emergency situations where the floating installation will no longer be within such a safe operation window or is in the process of leaving such a safe operation window. These are normally referred to as drift off or drive off situations dependent on the incident occurring. One will normally release the floating installation from the subsea installation by activating an Emergency Quick Disconnect Package (EQDP) when or before such situations occur.
The problem is to have enough time for the execution of an emergency disconnect in the event of an emergency situation. In a drift off/drive off situation of the floating installation, or if the heave compensator fails, there is normally very little time available to disconnect the riser from the wellhead. It has been found that activation of the Emergency Quick Disconnect (EQD) may take more time than is available.
There is therefore a need for increasing the available window for operations of an EQD in a riser, and thereby an increased operational window for a riser.
The object of the present invention is to provide an increased available window for operation of a riser. This is achieved with a joint and a method as defined in the attached claims.